1. Technical Field
The present invention relates generally to the wireless charging of a battery powered device; and more particularly to techniques for near field wireless resonance power delivery to a target device.
2. Related Art
All electronic devices require electrical power to operate. Mobile devices such as laptop computers and cell phones typically include a rechargeable battery that is recharged when the device is plugged into a power socket. Rechargeable batteries must be charged from wall power regularly to maintain battery life because rechargeable batteries discharge even when not used. The users of the mobile devices often suffer due to inaccessibility of electrical power for battery charging. In such a situation, the user must carry multiple batteries for continued operation of the mobile device. Requiring a user to carry backup batteries not only incurs the expense of the additional battery but requires transport space and increased transport expense.
Users of mobile devices usually carry power cables so that they can recharge the batteries of their mobile devices. These power cables are often misplaced or lost, inconveniencing the users. Quite often, the power cables are device specific and cannot be used in place of one another. Further, even with a power cable in hand, power sockets may be unavailable. This problem is a particular issue in airports or other public places, which users of the mobile devices frequent. In some critical applications, such as military applications and medical applications, it becomes dangerous if not disastrous to interfere with an ongoing activity/communication of a mobile device simply to recharge the device's battery.
Near field power delivery has been known for many years. Nikola Tesla first experimented with such power delivery many years ago, although his solutions were not viable for various reasons. Near field power delivery typically exploits magnetically coupled resonance, which allows two objects resonating at the same frequency to exchange energy with moderate efficiency. The frequency of such near field resonance may be much lower than wireless communication frequencies, e.g., 10 MHz for near field resonances compared to 2 GHz for wireless communications. Thus, near field power delivery shows much promise, although it is not yet commercially exploited.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of ordinary skill in the art through comparison of such systems with the present invention.